| With the development of computer, control, communication, and network technology, the demands of information exchange is rapidly spreading from enterprise management layer to bottom equipment layer. Field bus technology emerges under such environment. Various field equipment needed information are transmitted on standard and open network buses, which promotes the development of control system towards the direction of "distributed" , "networked" , and "intelligent" . Some influential field bus technologies have emerged and been widely used around the world in the last ten years. PROFIBUS, a filed bus system compliant to international standard IEC61158 and European standard EN50170, is the most popular field bus technology which develops quickly and features various products types, wide applications, and brilliant future. In order to keep up with the technical trends and help spread the application of field bus technology, it is urgent for us to research on PROFIBUS characteristics, to learn how to build and configure PROFIBUS networks, and to develop software/hardware products interfacing with PROFIBUS.With the widely spreading of Internet, applying TCP/IP protocol on Ethernet has already been the primary solution for industrial enterprises to build LANs and access to Internet. Researching on interfaces between field bus and Ethernet would be quite significant for improving the integration of enterprise information. Since Ethernet offers lower cost and broad users, researching and developing of field bus equipments based on embedded TCP/IP and Ethernet has been the focus of the industry, which is beneficial to lowering the enterprise networking cost, propelling the using of Ethernet as filed bus, and realizing equipment remote management via Internet.Basing on the networking reconstruction work of JFMT (Jinan First Machine Tool Group Co., Ltd.) FMS (Flexible Manufacturing System) automatic Workpiece-loading&Carrying system, the paper designs a PROFIBUS-DP control network with SIEMENS S7-300 PLC as core and a Ethernet control network which uses the self-developed remote measurement&control board as the field equipment. The paper also fulfills the connection of the two networks bythe development of upper monitor PC software, and realizes the real time control of the Workpiece-loading&Carrying system (including the Workpiece-Carrying-Vehicle) eventually.In the paper, remote measurement&control board, which is developed as general-purpose embedded field bus equipment, is to realize the real time control of the Workpiece-Carrying-Vehicle positioning process in the automatic Workpiece-Loading&Carrying system. The paper summarizes the hardware design of the remote measurement&control board and focuses on the realization of embedded TCP/IP on the board as well as the remote measurement and control method with UDP message.TCP/IP protocol' s realization is the key problem in the embedded equipment software design. Traditional TCP/IP consumes many resources to guarantee data reliability and data flow control. Because of its excessive complexity, traditional TCP/IP could not meet the real time requirement and run on the embedded equipment whose system resources are limited. For a better-embedded application, it is necessary for the paper to modify the traditional TCP/IP to improve its real time ability and reduce the consumption of memory spaces. The paper analyzes some basic protocols of the TCP/IP family in detail, such as ARP, IP, ICMP, and UDP. Considering the unique requirement of the remote measurement&control board, the paper provides the real time realization method of these protocols by modification of the traditional arithmetic on the premise of not violating the protocol standard.The paper also introduces how to build PROFIBUS-DP network as well as the method of network configuration and software/hardware setting. In addition, through the description of upper monitor PC software design flow, an interfacing method between PROFIBUS-DP network and Ethernet is also introduced in the paper. |
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